REMOVAL OF 2-NAPHTHOXYACETIC ACID FROM AQUEOUS SOLUTION USING QUATERNIZED CHITOSAN BEADS

The present study investigates the use of quaternized chitosan hydrogels for the adsorption of an aromatic organic carboxylate, 2-naphthoxyacetic acid (2-NAA), to demonstrate the applicability of this type of adsorbent towards the removal of naphthenic acids (NAs) from oil sands proces-saffected water (OSPW). The effects of varying three processing parameters on the physical and adsorption characteristics of the resulting adsorbents were investigated, namely the density, degree of cross-linking, and degree of quaternization of the hydrogel beads. Their effects on the swelling behaviour and Langmuir adsorption capacity of 2-NAA were reported. The Langmuir adsorption isotherm provided adequate fit for the equilibrium adsorption data (R-2 >= 0.99), while the pseudo second order rate equation described the kinetic adsorption data quite well (R-2 >= 0.95). The effects of adsorbate concentration, adsorbent dosage, agitation rate, ionic strength, pH, and temperature on the adsorption process were also studied. At the initial concentration of approximately 200 mg/L, up to 91 % of 2-NAA was adsorbed. The best quaternized chitosan hydrogel adsorbents reported in this study possessed a maximum adsorption capacity of 315 mg/g.